Study of dissolution parameter of ground granulated blast furnace slag as cement replacement on mechanical properties of mortar

Abstract

Abstract The current study was focused to find the impact of the dissolution of Ground Granulated Blast Furnace Slag (GGBS) in water before combining it with the other proportions of mortar. Two mixing types were used in the study. First, the conventional mixing method, wherein the GGBS was added with the cement and sand. Second, the new mixing method, wherein the GGBS was dissolved in water before adding to cement and sand. Five dissolution times (0, 1, 3, 6, 12 h) were studied with various percentages of GGBS as cement replacement (0%, 2.5%, 5%, 10%, 20%).The new mixing method has given higher compressive strength as compared to the conventional mixing method. The maximum compressive strength was obtained at 2.5% and 5.0% GGBS for a standing duration of 1 hr immersion in water. The higher compressive strength of mortar cubes was due to the hydrolysis of GGBS in water and was determined by the mobility of Ca and Si ions. As the ratio of Ca/Si decreased, the compressive strength was increased and was more prominent as long as the portlandite Ca(OH)2 was in active state. The compressive strength at earlier stage was developed because of the pozzolanic activity and mobility of ions.